Stereolithography apparatuses have been in practical use to form a three-dimensional object by irradiating a light beam onto a curable material and partially curing the material. Stereolithography apparatuses allow for easy creation of components such as machine parts designed with a CAD system, enabling verification and direct evaluation of the design (see Patent Document 1, for example).
A stereolithography apparatus includes a vat and an elevator platform, which is lifted and lowered in the vat. The vat is filled with photocurable liquid resin, which serves as a curable material. The vat includes an opening in the upper section, and a light beam is directed into the vat through the opening. When forming a three-dimensional object, the stereolithography apparatus first positions the elevator platform at a height lower than the liquid surface of the photocurable liquid resin by the thickness of the bottom layer of the three-dimensional object to be formed. Then, the stereolithography apparatus moves the recoater along the liquid surface to level the liquid surface. The stereolithography apparatus then scans a light beam over the necessary area using the scanner to cure the photocurable liquid resin and form the bottom layer of the three-dimensional object. Then, the stereolithography apparatus lowers the elevator platform by the thickness of the layer next to the bottom layer, or the second layer, and forms the second layer in the same manner as the bottom layer. The stereolithography apparatus successively forms each of the layers in order from the bottom layer in the same manner to form the three-dimensional object.